The proposed longitudinal California Lupus Epidemiology Study (CLUES) cohort will derive from the successful California Lupus Surveillance Project (CLSP), a Centers for Disease Control and Prevention (CDC)-funded population-based registry (n=890). Aims of CLUES are to: (1) Recruit and follow individuals identified in the CLSP to establish a population-based, longitudinal cohort with a unique balance of African American, Asian, Hispanic, and Caucasian individuals; (2) Create a state-of-the-art clinical and patient-reported data repository that includes information needed to further define and understand the epidemiology and outcomes of lupus; (3) Establish a state-of-the-art lupus biospecimen repository that includes serum and DNA from individuals in the CLUES cohort; (4) Perform high-impact research investigations to advance understanding of racial/ethnic and socioeconomic disparities in lupus; and (5) Support collaborative use of the CLUES data and biospecimen repositories for research investigations both in California and nationally, and work with community and organizational partners to ensure that study findings impact public health. Innovative research investigations will be undertaken to examine changes in epigenetic profiles over time and determine whether epigenetic factors contribute to ethnic differences in lupus outcomes; investigate novel patient-reported outcomes (PROs) in lupus and racial/ethnic differences in those PROs; and use new quality measures to understand and quantify how lupus nephritis is evaluated and treated in different racial/ethnic groups in the U.S. health care system. This range of projects, from the molecular to the health systems level, illustrates one of the unique features of this application. Other novel aspects are the diversity of the patient population; the depth of experience of the investigators with development and maintenance of patient cohort studies, clinical care of lupus, and lupus clinical, genetics, and PRO research; the diversity of data to be collected both to address specific investigations and to establish a resource for other investigators and future collaborations; and plans to collect biospecimens from the carefully characterized and diverse lupus cohort. We will recruit individuals from the CLSP cohort to participate in systematic annual telephone surveys that include information on disease status, PROs, and self-reported health utilization. A group of 400 patients, 100 from each of four racial/ethnic groups (African American, Asian, Hispanic, and Caucasian), will also undergo more intensive study. This group will have two research clinic visits that will include detailed clinical examinations by leading lupus physicians, collection of biologic specimens, completion of PRO measures, and collection of medical records. The proposed project leverages outstanding institutional resources and builds on the proven track-record of the investigators in (1) building successful administrative and management infrastructures, including a strong Advisory Committee, (2) developing and maintaining longitudinal cohort studies, and (3) creating effective systems for sharing clinical data and biospecimen resources.